Internal combustion engine



FIG. 1 is a front perspective view of an internal combustion engine in accordance with the present design;

FIG. 2 is a rear perspective view thereof;

FIG. 3 is a front view thereof;

FIG. 4 is a rear view thereof;

FIG. 5 is a left side view thereof;

FIG. 6 is a right side view thereof;

FIG. 7 is a top plan view thereof; and,

FIG. 8 is a bottom plan view thereof.

In FIGS. 1, 3, 5, 6, 7, and 8, portions indicated by broken lines do no constitute the claimed design. 

CLAIM The ornamental design for an internal combustion engine, as shown and described. 